CIFS: Adjust MTU credits before reopening a file
Currently we adjust MTU credits before sending an IO request
and after reopening a file. This approach doesn't allow the
reopen routine to use existing credits that are not needed
for IO. Reorder credit adjustment and reopening a file to
use credits available to the client more efficiently. Also
unwrap complex if statement into few pieces to improve
readability.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 6f1a5f5..085e914 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -222,6 +222,38 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
return rc;
}
+static int
+smb2_adjust_credits(struct TCP_Server_Info *server,
+ struct cifs_credits *credits,
+ const unsigned int payload_size)
+{
+ int new_val = DIV_ROUND_UP(payload_size, SMB2_MAX_BUFFER_SIZE);
+
+ if (!credits->value || credits->value == new_val)
+ return 0;
+
+ if (credits->value < new_val) {
+ WARN_ONCE(1, "request has less credits (%d) than required (%d)",
+ credits->value, new_val);
+ return -ENOTSUPP;
+ }
+
+ spin_lock(&server->req_lock);
+
+ if (server->reconnect_instance != credits->instance) {
+ spin_unlock(&server->req_lock);
+ cifs_dbg(VFS, "trying to return %d credits to old session\n",
+ credits->value - new_val);
+ return -EAGAIN;
+ }
+
+ server->credits += credits->value - new_val;
+ spin_unlock(&server->req_lock);
+ wake_up(&server->request_q);
+ credits->value = new_val;
+ return 0;
+}
+
static __u64
smb2_get_next_mid(struct TCP_Server_Info *server)
{
@@ -3678,6 +3710,7 @@ struct smb_version_operations smb21_operations = {
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
.wait_mtu_credits = smb2_wait_mtu_credits,
+ .adjust_credits = smb2_adjust_credits,
.get_next_mid = smb2_get_next_mid,
.revert_current_mid = smb2_revert_current_mid,
.read_data_offset = smb2_read_data_offset,
@@ -3775,6 +3808,7 @@ struct smb_version_operations smb30_operations = {
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
.wait_mtu_credits = smb2_wait_mtu_credits,
+ .adjust_credits = smb2_adjust_credits,
.get_next_mid = smb2_get_next_mid,
.revert_current_mid = smb2_revert_current_mid,
.read_data_offset = smb2_read_data_offset,
@@ -3881,6 +3915,7 @@ struct smb_version_operations smb311_operations = {
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
.wait_mtu_credits = smb2_wait_mtu_credits,
+ .adjust_credits = smb2_adjust_credits,
.get_next_mid = smb2_get_next_mid,
.revert_current_mid = smb2_revert_current_mid,
.read_data_offset = smb2_read_data_offset,